The invention relates to a passenger service unit for aircraft cabin systems. The passenger service units are connected through data buses to an aircraft central control for controlling and monitoring cabin lighting systems, a cabin public address system, displays, keyboards, sensors such as temperature sensors and air circulation sensors timers, counters, switches, and the like referred to herein as passenger service units and components of such passenger service units.
It is known to organize the open and closed loop controlling and monitoring of aircraft cabin systems electrically and electronically with the aid of an aircraft central control. The aircraft central control comprises one or two computers which control all individual passenger service units and/or components of the above mentioned cabin systems. The individual components such as lights, loudspeakers, temperature sensors, and the like, are connected to the computer or computers through data buses and the individual components do not contain any xe2x80x9cintelligencexe2x80x9d of their own. The components receive their instructions through the data buses and are capable of returning certain response signals to the central control. Such response signals, for example provide information whether the particular component is in the on or off state or whether it is functioning properly.
The just described conventional control system has certain drawbacks. For example, one such drawback is seen in that a multitude of conductors must be installed in the aircraft to form the data buses. The nature of such conductors makes the cabin layout rather unflexible with regard to increasing the system size, adding to the system functions, or modifying the system for example when changing a cabin layout to another cabin layout.
Another disadvantage of conventional systems is in the fact that the more complex a conventional system gets, the higher are the costs for performing testing operations that are required in order to obtain official licenses for the use of such systems. Moreover, changes made in a single passenger service unit or component conventionally require retesting the entire cabin system for official approval. Similarly, any change or addition to the central aircraft control for varying a capability or for adding capabilities also requires renewed testing of the entire system on the assumption that such changes or additions may have adversely affected the entire system, for example with regard to the system reliability. In other words, all components of a conventional system must be retested even if only one component was modified. Such requirements are officially imposed because it must be proven by the operator of the system that components which have not been modified by the addition of a new capability or several new capabilities, have not been affected by such addition or additions, or modifications. A new license is then issued only after the renewed proof has been provided to the licensing authority.
U.S. Pat. No. 5,369,584 (Kajiwara) discloses a control system for a vehicle with a central controller (30) connected through a data bus (34) to submain controllers (35, 36). One submain controller (35) is a power controller for operating the engine and the transmission directly in response to signals from engine sensors (13) and signals from transmission sensors (14) independently of the central controller. The other submain controller (36) is a drive controller and can respond to signals from a steering sensor (40), from a suspension sensor (15) and from a brake sensor (16), also independently of the central controller. The central controller (30) overrides the submain controller in response to certain sensor signals such as distance signals to a preceding vehicle measured by a sensor (31) directly connected to the central controller (30). The submain controllers do not have any programming capability that is independent of the main control.
The vehicle control system of Kajiwara is not suitable for use in a passenger aircraft cabin system because the system does not have to meet official aircraft safety standards, the known system does not provide personal/computer facilities to the passengers of the vehicle, and the power and drive controller (35, 36) cannot be programmed, much less reprogrammed.
U.S. Pat. No. 4,774,514 (Hildebrandt et al.) describes a method and system for carrying out passenger-related and flight attendant-related functions in a passenger aircraft. The main purpose of the Hildebrandt et al. invention is to use permanently installed wiring in an aircraft cabin for several different cabin layouts by providing a decoder/encoder unit (DEU) between a central data bus that leads to the aircraft central control computer and individual passenger service unit. Due to the decoder/encoder units the Hildebrandt et al. system is very flexible in its ability for changing a cabin layout. However, the economy and weight of the permanent wiring leaves room for improvement. The Hildebrandt et al. system still requires a substantial number of individual conductor wires, a passenger service unit, also referred to as passenger supply and information unit, and the respective decoder/encoder unit. More specifically, up to seventeen conductor wires each with an average length of about 3.8 meters may be required between a decoding/encoding unit and the respective passenger service unit. Assuming that there are on average about 150 passenger service units in a passenger aircraft, substantial reductions in wiring requirements would be very desirable.
In view of the foregoing it is the aim of the invention to achieve the following objects singly or in combination:
to provide a passenger service unit for an aircraft with a passenger interface and supply adapter which is individually programmable and can function independently of any aircraft central control;
reprogram the same passenger interface and supply adapter for different purposes and different functions;
to relieve or reduce the operations and/or storage capabilities of the central computer of the aircraft central control;
to reduce the number of electrical conductors for transmitting signals between the above-mentioned decoder/encoder unit and the respective individual passenger service unit for achieving a respective weight reduction and a reduced effort and expense for the wiring installation; and
to construct the passenger interface and supply adapter in such a way that it functions as a buffer or interface between the aircraft central control and any other passenger service unit, whereby modifications of any passenger service unit or component such as reprogramming its interface and supply adapter will not affect any other passenger service unit or component, whereby retesting of the entire system is avoided when system changes or system expansions are made and only the changed passenger service units or added passenger service units need to be tested.
The above objects have been achieved according to the invention by a passenger service unit (PSU) for an aircraft cabin, said passenger service unit comprising at least one passenger service component, a passenger interface and supply adapter (PISA) (10) for controlling said at least one passenger service component independently of an aircraft central control (12), said passenger interface and supply adapter (10) comprising at least one programming input/output (17) for programming or reprogramming said passenger service unit independently of said aircraft central control (12), a signal conductor bus (11) for connecting said passenger interface and supply adapter (10) to said aircraft central control (12), said passenger interface and supply adapter (10) further including a processing unit (14) connected to said programming input/output (17) for individually programming said processing unit (14) and thereby controlling said at least one passenger service component in said passenger service unit independently of said aircraft central control (12), said passenger interface and supply adapter (10) further comprising a memory (15) operatively connected to said programming input/output (17) for program storing, wherein said passenger interface and supply adapter (10) functions as a buffer between said aircraft central control (12) and said passenger service unit, so that said passenger service unit is modifiable by individual programming without affecting any other passenger service unit or units.
Such a separate passenger interface and supply adapter is also referred to herein as a multi-purpose module (10) capable of operating independently of the central control and thereby relieving the central control by controlling and/or monitoring certain functions, particularly passenger related functions and flight attendant related functions in a decentralized manner so that the central aircraft control remains unaffected by the decentralized operations, whereby the costs for testing to obtain the required official licenses have been substantially reduced because retesting of the central control and the entire system is avoided and only the multi-purpose module needs to be retested if and when it has ben reprogrammed.
Another advantage of the invention is seen in that the control of a cabin system or systems through a plurality of multi-purpose modules (10) is rather flexible, particularly with regard to changes and expansions in the system functions that can be performed by the multi-purpose module or modules. Open and closed loop control functions, as well as monitoring can be efficiently integrated into such a multi-purpose module.
Moreover, the multi-purpose module has a so-called xe2x80x9cstand alonexe2x80x9d capability so that individual components of any cabin system can be controlled and monitored by the module to keep these components operable independently of any other passenger service units or components. This feature of the module is particularly useful in connection with old control programs because existing cabin systems can be retrofitted in a simple manner with one or several multi-purpose modules. The programming and testing of such retrofitted multi-purpose module or modules can be performed independently of the aircraft central control and is therefore substantially less expensive. It is also an advantage that such modules have a very small space requirement for their installation with the added bonus of requiring but a small power consumption for operating the module. Where certain components such as lamps or other power consuming components are operated through the multi-purpose module, it is preferred that module controlled driver stages or power amplifiers are provided in the power supply circuit for the respective component or components.
It is also preferred that the multi-purpose module is equipped with its own power supply unit, and that at least one voltage supply for other components is provided by the module, especially a controlled voltage.
According to the invention there is further provided a passenger service system in an aircraft cabin, said system comprising a plurality of passenger service units (4), an aircraft central control (12) for centrally controlling said passenger service units (4), each passenger service unit comprising at least one passenger service component and a passenger interface and supply adapter (PISA, 10) for controlling said at least one passenger service component in said aircraft cabin independently of said aircraft central control (12), said passenger interface and supply adapter 10) comprising at least one programming input/output (17) for programming said passenger service unit independently of said aircraft central control (12), a signal conductor bus (11) for connecting said passenger interface and supply adapter (10) through said signal conductor bus (11) to said aircraft central control (12), said passenger interface and supply adapter (10) further including a processing unit (14) connected to said programming input/output (17) for individually programming or reprogramming said processing unit (14) and thereby controlling said at least one passenger service component independently of said aircraft central control (12), said passenger interface and supply adapter (10) further comprising a memory (15) operatively connected to said programmable input/output (17) for program storing, wherein said passenger interface and supply adapter (10) functions as a buffer between said aircraft central control (12) and said passenger service units, so that any one of said passenger service units is modifiable by individual programming without affecting any other passenger service unit or units.
The above outlined advantages of the invention are equally achieved by the present passenger service system.
In both embodiments of the invention the present passenger interface and supply adapter or multi-purpose module (10) is preferably hermetically sealed in its installation housing so that it is not sensitive against external mechanical influences.
Moreover, it is advantageous to reduce even the small power consumption of the multi-purpose module by providing it with a so-called standby mode of operation, which can, for example be achieved by a respective programming of the individual CPU of the module which switches the module into a standby mode if the module has been inactive for a defined time period.
In a preferred embodiment the module is equipped with a freely programmable input/output unit (I/O) for supplying, for example, discrete analog and digital data to the module. Moreover, the multi-purpose module is equipped with a memory for storing one or more programs such as control programs that are permanently stored in the memory, whereby the memory size of the aircraft central control can be reduced or supplemented. The databus between the module and the central control permits, for example, a remote programming of the module through the central control in addition to the individual programming of the module independently of any programing through the central control. These features of the invention substantially reduce the wiring requirements between the module and the individual passenger service components as compared to systems without such modules.